BlockDiagram
The MAXREFDES178 reference design hardware consists of two boards:
- Connectivity Board:
This is the board placed at the rear part of the enclosure, next to the TFT LCD. The Connectivity Board is based on the MAX32666 Dual-Core Arm® Cortex-M4 Microcontroller with Bluetooth 5. The main functions of this board are to provide interfaces and power to the platform. USB communication, debugging and programming, LCD, touchscreen interfaces, a micro SD Card slot and an IMU sensor are placed on this board.
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AI Board:
The AI board has the same form factor and size as the connectivity board. It is attached to the front part of the enclosure. This board hosts two MAX78000 processors. Both MAX78000 processors are exactly the same. For the sake of clarity in the schematic diagrams and documentation, MAX78000 processors are named as MAX7000-Video (or MAX78000-Image) and MAX78000-Audio.- MAX78000-Video (or MAX78000-Image) (U4): This processor is mainly responsible for AI vision applications. The image sensor of the MAXREFDES178 reference design is connected to this processor via the PCIF interface. For camera control and configuration, there is also an SCCB interface between the image sensor and the processor. The processor configures the image sensor with the desired resolution and captures images using the PCIF interface.
MAX1574 White LED Charge Pump IC is controlled with the MAX78000-Video processor. There are two white LEDs around the image sensor LEDs.
- MAX78000-Audio (U6): For audio applications such as keyword detection and speaker identification, this MAX78000 processor can be used. It is connected to an onboard MEMS microphone via an I2S interface as well as MAX9867 Ultra-Low Power Stereo Audio Codec.
Connectivity Board and AI Board are connected via a 0.30mm pitch, 33-circuit flex cable. The part number for the cable is Molex 150150233.
Alternatively, if it is needed to place the front and the rear part of the enclosure apart, a longer version of this cable can be used.
The flex cable carries power to the AI board from the Connectivity Board. Besides the power lines, there are multiple interfaces such as QSPI, I2C and GPIO signals available.
The existing MAXREFDES178 example projects are based on the QSPI interface between MAX32666 and MAX78000-Video / MAX78000-Audio processors on the platform. MAX32666 is configured as QSPI master and MAX78000 processors are configured as QSPI slave devices.